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91.
Hussain M. Sakhawat Ahmad Jamil Mazhar-ul-Haque Khattak Gul Dad 《Transition Metal Chemistry》1986,11(4):155-159
Summary We have carried out low temperature magnetic susceptibility measurements and a redetermination of the crystal and molecular structure of bis(1,5-diazacyclooctane)nickel(II) perchlorate dihydrate from three-dimensional intensity data collected on a CAD4 diffractometer. The structure was refined by full-matrix least-squares to the R value of 6.3% for 1501 observed reflections. The positions of the hydrogen atoms were obtained from the diffraction data. Contrary to our earlier conclusions drawn by inspection of molecular models of bis(diazacyclooctane) complexes, the axial sites in the actual crystal structure are open for ligation. The Ni-N bonds are, however, sterically protected by the coplanar N-H bonds, allowing maximum ligand-field stabilization for the squareplanar geometry around the nickel atom. The observed magnetic transition from a diamagnetic state at room temperature to a paramagnetic state at 78 K is explained on the basis of long-range exchange interactions along sterically unshieldedz axis. The crystal structure is compared with other similar structures. 相似文献
92.
Hassan Wafi Garba Muhammad Sabiu Abdullahi Mohamad Shazwan Shah Jamil Nor Azam Endot 《Molecules (Basel, Switzerland)》2021,26(19)
The reduction of 4-nitrophenol to 4-aminophenol by sodium borohydride was used as a model to test the catalytic activity of copper(II) complexes containing N,O-chelating Schiff base ligands. In this study, a series of copper(II) complexes containing respective Schiff base ligands, N′-salicylidene-2-aminophenol (1), N′-salicylidene-2-aminothiazole (2), and N,N′-bis(salicylidene)-o-phenylenediamine (3), were synthesized and characterized by elemental analysis, Fourier transform infrared (FT-IR), UV-Visible (UV-Vis) and electron paramagnetic resonance (EPR) spectroscopies. The results from the 4-nitrophenol reduction showed that 3 has the highest catalytic activities with 97.5% conversion, followed by 2 and 1 with 95.2% and 90.8% conversions, respectively. The optimization of the catalyst amount revealed that 1.0 mol% of the catalyst was the most optimized amount with the highest conversion compared to the other doses, 0.5 mol% and 1.5 mol%. Recyclability and reproducibility tests confirmed that all three complexes were active, efficient, and possess excellent reproducibility with consistent catalytic performances and could be used again without a major decrease in the catalytic activity. 相似文献
93.
Ujjal Debnath Mubasher Jamil Surajit Chattopadhyay 《International Journal of Theoretical Physics》2012,51(3):812-837
In the framework of Fractional Action Cosmology (FAC), we study the generalized second law of thermodynamics for the Friedmann
Universe enclosed by a boundary. We use the four well-known cosmic horizons as boundaries namely, apparent horizon, future
event horizon, Hubble horizon and particle horizon. We construct the generalized second law (GSL) using and without using
the first law of thermodynamics. To check the validity of GSL, we express the law in the form of four different scale factors
namely emergent, logamediate, intermediate and power law. For Hubble, apparent and particle horizons, the GSL holds for emergent
and logamediate expansions of the universe when we apply with and without using first law. For intermediate scenario, the
GSL is valid for Hubble, apparent, particle horizons when we apply with and without first law. Also for intermediate scenario,
the GSL is valid for event horizon when we apply first law but it breaks down without using first law. But for power law expansion,
the GSL may be valid for some cases and breaks down otherwise. 相似文献
94.
95.
M. Umar Farooq Mubasher Jamil Muneer A. Rashid 《International Journal of Theoretical Physics》2010,49(9):2278-2287
We consider the new agegraphic dark energy model with the help of the quantum corrections to the entropy-area relation in
the setup of loop quantum gravity. Employing this new form of dark energy so called entropy-corrected new agegraphic dark
energy (ECNADE), we investigate the model of interacting dark energy and derive its equation of state (EoS). We study the
correspondence between the K-essence, tachyon and dilaton scalar fields with the interacting (ECNADE)in the non-flat FRW universe.
Moreover, we reconstruct the corresponding scalar potentials which describe the dynamics of the scalar field. 相似文献
96.
Mubasher Jamil 《International Journal of Theoretical Physics》2010,49(1):62-71
I present a model in which dark energy interacts with matter. The former is represented by a variable equation of state. It
is shown that the phantom crossing takes place at zero redshift, moreover, stable scaling solution of the Friedmann equations
is obtained. I show that dark energy is most probably be either generalized phantom energy or the generalized Chaplygin gas,
while phantom energy is ruled out as a dark energy candidate. 相似文献
97.
Mubasher?Jamil 《International Journal of Theoretical Physics》2010,49(1):144
I present a model in which dark energy interacts with matter. The former is represented by a variable equation of state. It is shown that the phantom crossing takes place at zero redshift, moreover, stable scaling solution of the Friedmann equations is obtained. I show that dark energy is most probably be either generalized phantom energy or the generalized Chaplygin gas, while phantom energy is ruled out as a dark energy candidate. 相似文献
98.
Georges Dénès Jamil Hantash Abdualhafeed Muntasar Philip Oldfield Alan Bartlett 《Hyperfine Interactions》2006,170(1-3):145-158
Ionic conductors are solids that have a large number of defects and easy pathways that make it possible for ions to move over long distances in an electric field. In order to be mobile an ion must be small and have a low charge. The fluoride ion is the most mobile anion. The highest performance fluoride ion conductors contain divalent tin, and have a highly layered crystal structure related to the CaF2 fluorite type. BaSnF4 has the α-PbSnF4 structure, which is a √2/2?×?√2/2?×?2 superstructure of the fluorite type, where the tetragonal unit-cell and the value of the a and b parameters being equal to half the diagonals of the (a,b) face of fluorite are due to the loss of the F Bravais lattice, and the Sn Sn Ba Ba order along the c parameter is at the origin of the doubling of the c parameter. The BaSnF4 material was prepared first by Dénès et al. (C. R. Acad. Paris C, 280: 831, 1975), and its superionic properties were characterized by Dénès et al. (Solid State Ion., 13: 213, 1984). It was found to have a conductivity three orders of magnitude higher than that of BaF2, with an ionic conduction rate τ i?>?0.99. No BaSnF4 was obtained by the aqueous medium, when aqueous solutions of SnF2 and Ba(NO3)2 are mixed together; BaSn2F6 was obtained instead. In a new development of this work, BaSnF4 has been obtained by the wet method for the first time. X-ray powder diffraction showed that the BaSnF4 phase obtained by the wet method varies substantially from one sample to another: (a) signification variations of the c parameter of the tetragonal unit-cell reveals that the interlayer distance is sensitive to the leaching conditions, possibly because some of the leached ions remain in the interlayer spacing; (b) large variations of the crystallite dimensions and, as a result of the two-dimensionality of the structure, a strong crystallite dimension anisotropy are observed, with d∥?d⊥, where d∥ and d⊥ are the crystallite dimensions parallel to the four-fold main axis, and perpendicular to it, respectively, showing that the layers are very thin and the interlayer interactions are very weak. Variable temperature Mössbauer spectroscopy showed an unusual large variation of the quadrupole splitting with temperature. A tentative explanation based on unusually large bond angles has been proposed. 相似文献
99.
T. Kousksou A. Jamil S. Gibout Y. Zeraouli 《Journal of Thermal Analysis and Calorimetry》2009,96(3):841-852
This paper presents some results obtained by Differential Scanning Calorimetry (DSC) for characterizing the phase transition
within an emulsion. The dispersed substances are either hexadecane, octadecane, water or binary solution. A non-equilibrium
model taking into account the inter-phase heat transfer between the emulsifying medium and the dispersed droplet is proposed
and explains the main experimental features. 相似文献
100.
A direct method is described for the determination of molybdenum in mg amounts of organomolybdenum compounds by flame emission or atomic absorption spectrometry. Air/acetylene, air/hydrogen and dinitrogen oxide/acetylene flames were used. The emission of molybdenum oxide is found to be analytically useful in the hydrogen-based flames while the acetylene-based flames are better for atomic absorption. Various organomolybdenum compounds were analysed by both methods as well as by an alternative spectrophotometric method, with satisfactory agreement. The procedure involves simply dissolving the sample in a mixed solvent and aspirating the solution into the flame. 相似文献